Master
English

A phylogenomic and taxonomic study of ummidin spiders (Halonoproctidae, Mygalomorphae, Araneae) from Southeast Asia using Ultra Conserved Element (UCE)

Number of pages150
Master program titleBiodiversity and Systematic
Defense date2022-05-25
Abstract

The present work is an attempt to clarify the phylogeny and systematic of the trapdoor spiders belonging to the subfamily Ummidiinae (Halonoproctidae, Mygalomorphae, Araneae), more specifically the three genera Ummidia Thorell 1875, Conothele Thorell 1878 and Latouchia Pocock 1901. The research is based on genetic data generated from 119 samples collected during the last 50 years and mainly composed of Southeast Asian taxa. A phylogenomic analysis was carried out on this dataset that includes both Ultra Conserved Elements (UCE) and transcriptomes. The use of UCE in phylogenomic studies was first proposed by McCormack et al. (2012) and shown the ability of the method to resolve systematic issues. A set of 14799 DNA probes specifically targeting 1121 UCE loci in Arachnida taxa was used to generate the dataset. The bioinformatic pathway commonly used was upgraded by scripts generated during the study. The analysis carried out allows to produce visual statistical information about the decrease in capture rate with sample age, the variation of this rate considering the DNA quality and the Index hoping rate. The phylogenetic results suggest the colonization of Conothele Thorell, 1878 from Asia to the Southwest Pacific Islands and Australia and reveal the presence of a new genus closely related to Ummidia in Southeast Asia. Also, the taxonomic analysis combined with the phylogeny allow to highlight the presence of two more new Halonoproctidae genera closely related to Latouchia. Moreover, the phylogeny and time divergent analysis combined with a precise assessment of distribution areas of the different clades retrieved also permit to discuss the biogeography of these groups. The results help to understand the more likely relationship between the current distribution of Ummidiinae and the geological history of southeast Asia. This history involving lots of events such as the disapereance of the Tethys Sea and the continuous uplift of the Eurasian tectonic plate. This rising induced by the northward drift of the Indian tectonic plate, has mainly affected the Tibetan plateau. Some specific changes resulting from these geologic events have been theorized under the form of the Proto-Mekong sedimentary basin network hypothesis (Licheng et al., 2021). This hypothesis involves the formation in Asia of a large network of basins connected by the proto-Mekong. This ancient river system was crossing Southeast Asia from north to south. The subsequent changes in topology and drainage induced by continuous Indian northward drift would have had a significant effect on the overall diversification and dispersal process of ummidin spiders. The formation of these basins is presented here as the first event of divergence among the Ummidiinae between 70 and 115 milion years ago. This event of divergence leading to a first group occuring north-east of the present Mekong distinct from the common ancestor group occuring South-West of the Basins network. This first group lead to Latouchia and the two closely related new genera which are endemic to southeast Asia. The second group diverged into Conothele and Ummidia. This general uplift has probably separated the Ummidia from the third new genus with the formation of the Himalayas.

Keywords
  • Systematic
  • Biodiversity
  • Araneae
  • Mygalomorphae
  • Halonoproctidae
  • Ummidiinae
  • Ultra conserved element
  • Trapdoor spiders
  • Phylogenetic analysis
Citation (ISO format)
NISSILLE, Daniel Alain. A phylogenomic and taxonomic study of ummidin spiders (Halonoproctidae, Mygalomorphae, Araneae) from Southeast Asia using Ultra Conserved Element (UCE). Master, 2022.
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Master thesis
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Identifiers
  • PID : unige:161425
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Creation08/06/2022 09:58:00
First validation08/06/2022 09:58:00
Update16/03/2023 06:45:09
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